This invention relates to a microelectronic package comprising a printed circuit board enclosed within a metal housing. More particularly, this invention relates to such microelectronic package wherein the metal housing includes side walls having integral tabs that secure the board and ground the housing to the board to shield the board from spurious radio frequency signals.
A common microelectronic package comprises a printed circuit board enclosed within a metal housing. Electronic components are mounted on a top, or first, face of the board and connected to a circuit trace to carry out desired electrical operations. Ground connections to the components are made to a metal layer submerged below the board face, referred to as a ground plane. Depending upon the particular board design, the ground plane may also may wrap around the edge of the printed circuit board and extend to the lower face.
The metal housing forms a radio frequency shield, which is more commonly referred to as an RF shield. The housing surrounds the printed circuit board and protects against ambient radio frequency signals that would otherwise create noise in the electrical signals processed by the board. Also, the metal housing contains radio frequency emissions by the board that might otherwise interfere with nearby electronic devices. For these purposes, the board is connected to the ground plane of the board. Optimum grounding is obtained by a multiplicity of connections spaced periodically about the board. The art provides many designs for such metal housings, commonly utilizing fasteners such as screws. Nevertheless, there remains a need for an improved metal housing into which the printed circuit board may be readily and securely assembled and which provides a reliable contact to the ground plane.